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DTC C1807: FCM/LDW/AHB target deceleration signal
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect DTC may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.
 
 
OPERATION
The ASC-ECU communicates with the FCM/LDW/AHB-ECU via CAN bus lines.
 
 
 
DTC SET CONDITIONS
If the ASC-ECU receives an abnormal signal from the FCM/LDW/AHB-ECU with the FCM activated (automatic braking applied), it will set the DTC.
 
 
 
PROBABLE CAUSES
  • Wiring harness or connector failure of CAN bus line
  • Malfunction of FCM/LDW/AHB-ECU
  • Malfunction of ASC-ECU
 
 
 
 
DIAGNOSIS
STEP 1. Using scan tool MB991958, diagnose the CAN bus lines.
Use scan tool MB991958 to diagnose the CAN bus lines.
Is the check result normal?
Go to Step 2
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ). On completion, go to Step 2.
 
STEP 2. Scan tool MB991958 other system DTC
Is DTC No.C1798 also set in the FCM/LDW/AHB-ECU?
Is DTC C1798 set?
Troubleshoot the relevant DTC (Refer to ).
Go to Step 3
 
STEP 3. Check whether the DTC is set again.
(1) Erase the DTC.
(2) Ignition switch "LOCK" (OFF)
(3) Ignition switch "ON"
Is DTC C1807 set?
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ).
The procedure is complete.